Stabilization of essential oils



Patented May 12, 1942 iJNi 2,282,808 STABHJZATION OF ESSENTIAL OILS NoDrawing. Original application September 23,

1938, Serial No. 231,344. Divided and this application November 22,1941, Serial No. 420,132

7 Claims.

The present invention relates to the stabilization of essential oils andproducts containing the same, by treating them with the concentratedwater soluble extract of cereals and grains, and particularly when thestabilizing activity of that extract is increased in potency by heattreatment.

It is among the objects of the present invention to provide improvedstabilized essential oils, or compositions containing the same subjectto oxidative deterioration.

Still further objects and advantages will appear from the more detaileddescription set forth below, it being understood, however, that thismore detailed description is given by way of illustration andexplanation only, and not by way of limitation, since various changestherein may be made by those skilled in the art without departing fromthe scope and spirit of the present invention.

In accomplishing the above objects, it has been found most satisfactoryto incorporate in products subject to deterioration the water solubleextract in concentrated form of the cereals and grains such as corn,barley, oats, hominy, tapioca, rye, rice, wheat, buckwheat, etc.material for extraction contains less than 0.75% total phospholipins andless than 10% of glyceride content and it is preferably in a fine stateof division. The cereal extract derived from oats and maize preferablyin raw unbleached condition, dry milled and in flour or divided formgives the highest yield of stabilizing activity and is far moredesirable. The cereals produce the most acceptable extract because oftheir low oil content which seems to enhance the production of asubstantially oil-free extract as contrasted to the high oil containingmaterials in which the antioxidants are not as readily susceptible towater extraction.

Although the water soluble extract may be prepared in many differentfashions and may be added at many stages to products subject todeterioration, it has been found most satisfactory to prepare suchextract by grinding or di- 1 viding the cereal and then submer'ging itin or extracting it with water or an aqueous material which is to beused in the product or processing of the organic material to bestabilized.

Asia general rule, the cereal undissolved portion may be removed byfiltration, or the liquid may ;be removed by decanting, centrifuging orsimilar process, and the time of extraction may vary from a few secondsto a period of several hours or longer. The aqueous solvent may beemployed either at room temperature or higher.

To 1 pound of cereal, there may be used, for example, 1 gallon of wateror more, dependent The preferred moved without substantially decreasingthe activity of the extract by vacuum distillation, by drying, at roomtemperature, or in a reducing atmosphere, etc., and the extract willtake the form of a brown pasty material or a dry powdery grayishmaterial, generally hygroscopic in character.

The extracts may not be completely soluble in the essential oil to bestabilized, but this will not decrease their efiiciency as stabilizers.Where desired, the insoluble material may be filtered off preferablyfollowing heating in the oil being stabilized to a temperature in excessof 250 F. and desirably in excess of 350 F.

This extract, in contradistinction to the crude vegetable oils,lecithin, etc., is not only unaffected by heat treatment, but isactually activated under conditions of heat. When the extract isutilized in organic products containing essential oils that are normallyprocessed at high .temperatures, or to which a high temperaturetreatment may normally be applied, minute percentages of the extractwill give a marked stabilizing action.

The essential oils or products containing the same may be treated withthe concentrated water soluble extract of the cereals to markedlyimprove their stability, and the stabilizing effect is particularlyobserved when the extract is heated in the oil to temperatures in excessof 250 F. and desirably in excess of 350 F.

Although the concentrated water soluble extract is preferred for usewith the organic materials containing essential oils described herein,

4 where advisable, the unconcentrated water solule extract of thecereals may also be employed.

Essential oils particularly are subject to rapid deterioration when inemulsified form and the use of the water soluble extract in the dispersewater phase will materially retard such deteriora-. tion.

The concentrated extract obtained contains a certain amount ofcarbohydrate material as a result of which charring is produced when theextract is heated in the presence of the oxidizable material. Regardlessof the charring, however, the extract, as indicated in the examples,becomes increasingly effective at temperatures in excess of about 250Rand particularly at 400 F. or above so that it may readily be used inconnection with materials that are normally processed at hightemperatures and where other antioxidants, and particularly the oilsoluble antioxidants would be inactivated or at least substantiallyreduced in activity.

Moreover, the extracts described, whether evaporated to dryness or not,are frequently more effective than the unextracted cereals from whichupon the degree of concentration desired. Fol- :2 they were removed, andafter being in contact lowing a thorough mixture, the watgrlnay bergwith the oxidizable materials for long periods,

. contained therein.

the treated materials retain their improved status for a longer periodthan if the original cereal were used.

Another distinct advantage in this treatment is that the presence ofbulky fibrous or starchy materials is avoided when the extract isemployed;

The extracts of the present invention, therefore, differ remarkably fromother oil soluble antioxidant materials, such as, for example, lecithin,crude vegetable oils, etc., in that they contain a quantity ofcarbohydrate material, they are not deactivated at elevatedtemperatures, but even become more active at temperatures as high as 400F., for example, and they have more continued potency for longer periodsof time.

It has also been observed that the relative rate of activation underconditions of heat treatment is far greater when the extract is utilizedthan when the proportionate amount of the unextracted cereal isutilized.

For example, when flour is activated under conditions of heat in anoxidizable oil, its potency will be increased to only a small portion ofthe increase observed when the extract of that cereal used inproportionate amounts is similarly heated.

The extracts described may be applied, particularly when heat activated,to the essential Oils themselves and also to the pharmaceutical or foodpreparations, creams, and other products containing the same.

Although the unconcentrated extract may be utilized, it is preferablefor'purposes of this invention to use the concentrated or dry extractsafter removal of the aqueous solvent. Where water is normally used inthe processing of organic materials, there may be employed either theconcentrated extract or the unconcentratcd extract in a dilute form.

There may also be employed, less desirably than the cereals, thesubstantially oil free seeds for purposes of extraction. For example,those oily seeds which contain in excess of 45% of oil and wherein freeoil is released during any macerating or grinding process may not bereadily extracted with an oil insoluble solvent such as water.

Following expression or extraction of a substantial portion of the oil,the residue may be extracted and the extract so obtained may be employedas an antioxidant in the essential oils, and products containing thesame, and particularly activated under conditions of heat.

The cereals and to a greater degree the de-oiled or low oil containingseeds even without extraction of the water and/or alcohol solubleportion exhibit much more marked antioxidant activity after beingsubjected to temperatures in excess of 250 F. and more desirably inexcess of 400 F. and particularly in the presence of the oxidizablematerial.

However, in accordance with the present invention it is preferred to usethe water extract of such materials.

Among other less preferred materials are the substantially. dry seedscapable of powdering without releasing free oil during a maceratingprocess. For example, such seeds as cottonseed or soya may be employedparticularly after the expression or extraction of the glyceride oilsCare must be exercised to remove all possible water insoluble materialswhen preparing, for example, the Water soluble extract. Any milkysuspension obtained during careless or incomplete water extraction willconoils. It is desirable to have the extract substantially free of waterinsoluble materials such as would be present in a milky suspension andwhich water insoluble materials would prove detrimental to thepreparation of the extract.

The extracts of the seeds difier from the extracts of the cereals inthat the seed extracts are considerably higher in carbohydrate content,will char and will discolor oils particularly under conditions of heatmore readily than the extracts of the cereals.

In addition to using water as the extracting medium, alcohols may bealso employed, although they are less desirable. Among the alcohols thatmay be used are ethyl and less preferably methyl, butyl, propyl, andaccepted denatured types of alcohols. In certain cases it is alsopossibleto use polyhydric alcohols such as glycerol or other glycols,but as a general rule these polyhydric alcohols are not particularlysatisfactory. The alcoholic extracts may desirably be subjected to anoil solvent extraction so as to remove such of the glycerides as happento be present. This will not materially alter the efiectiveness of theex tract and particularly where the maximum water solubility isrequired, will be of distinct advantage. Mixtures of the alcohols andwater, of course, may be employed. Oil extracting solvents such ashexane should not be employed. The alcohol and water types of solventare included by the expression XOH where X represents hydrogen, or a lowmolecular weight aliphatic group.

Although the cereals are always preferred in divided form and althoughin certain cases the oil bearing seeds and nuts, the oil content ofwhich has been reduced to below 10%, may be utilized for extraction, itis possible in some cases to combine with these materials or to usealone other beans such as the cacao bean, from which a large proportionof the oily and fatty materials have been extracted or expressed, or thecoffee bean in unroasted condition, both of which materials shouldpreferably be in powdered form before extraction. Other similarmaterials containing water extractable carbohydrates, and, to a lesserdegree, phospholipins in combination with such carbohydrates may also beemployed.

The heat treatment for purposes of activation referred to herein should,as indicated, be desirably carried out in the presence of the oxidizablesubstance and should be carried out at a temperature in excess of 250 F.The higher the temperature up to about 450 F., the greater will .be theincrease in antioxidant activity and the proportionate increase will befar greater at temperature ranges in excess of 350 F. For example, whenthe heat treatment is carried out at 400 F. to 450 F., a much greaterincrease in antioxidant effect will be produced than where the heattreatment is only 250 F. to 300 F. For this reason it is desirablewherever practicable to subject the oxidizable material to a heattreatment of about 400 F. to 450 F. with a small amount of thestabilizing material described herein.

By the term essential oils is meant the flavoring oils such as oil oflemon, oil of orange, oil of peppermint, oil of Wintergreen, oil ofcloves, oil of Sassafras, and the other essential oils and also thevarious perfume oils.

There are also included food compositions which may include or containin a small proportion these essential oils as well as the pharmaceuticalcreams including cold cream, vanishing tain water insoluble materialsincluding glyceride 15 cream, shaving cream, etc., and all of which aresubject to oxidation and contain varying proportions of these essentialoils.

The antioxygenic extracts referred to herein may be added to theessential oils themselves in amounts ranging from 0.1% to or more and tothe products containing the essential oils in amounts ranging from 0.02%to 2.5%.

Moreover, the essential oils, particularly in their substantially purecondition, may be homogenized and dispersed in the disperse phase of anemulsion where the continuous aqueous phase comprises the water andalcoholsoluble extracts referred to in accordance with the presentinvention. For example, oil of orange or oil of lemon may be homogenizedin the concentrated water extract of corn flour and the emulsion thusobtained may be utilized either as such or for addition to foodcompositions, whereby such food composition will be stabilized againstoxidative deterioration.

Under these conditions where the essential oil is homogenized in thecereal extract, the essential oil may comprise only from 3% to by weightagainst the weight of the cereal extract.

Following or during homogenization of the essential oil in the extractprepared in accordance with the present invention, the emulsion formedwith the essential oil or composition containing the same is subjectedto the elevated temperature of 250 F. or more in order to obtain thehighly active and enhanced antioxygenic effect.

The present application is a division of application Serial No. 231,344filed September 23, 1938, which has matured into patent 2,273,062,issued Feb. 17, 1942.

Having described my invention, what I claim i 1. A compositioncontaining a substantially unoxidized essential oil, said essential oilbeing subject to oxidative deterioration upon standing or heating in thepresence of air and said composition containing sufiicent substantiallyunoxidized oil to produce deterioration of the composition uponoxidative deterioration of said oil, said composition containing thereaction product of a relatively small amount of an oil insoluble,carbohydrate containing fiber free and starch free antioxidant materialextracted by a solvent selected from the group consisting of water anda1- cohol from a finely divided raw unbleached low oil and low lecithincontaining cereal fiour, said antioxidant material having been dispersedthroughout the body of the composition, said reaction product havingbeen formed by heating said antioxidant material with the oil at atemperature of at least about 250 F.

2. A composition containing a substantially unoxidized oil of orange,said oil of orange being subject to oxidative deterioration uponstanding or heating in the presence of air and said compositioncontaining sumcient substantially unoxidized oil of orange to producedeterioration of the composition upon oxidative deterioration of saidoil, the composition containing the reaction product of a relativelysmall amount of an oil insoluble, carbohydrate containing fiber free andstarch free antioxidant material extracted from the cereals by a solventselected from the group consisting of water and alcohol dispersedthroughout the body of the composition, said reaction product havingbeen formed by heating said antioxidant material with the oil at atemperature of at least about 250 F.

3. A substantially unoxidized oil of lemon normally subject to oxidativedeterioration and development of rancidity upon standing or heating inthe presence of air, said oil containing the reaction product of 0.2% ofthe concentrated fiber and starch free carbohydrate water solubleextract of dry milled maize flour, said extract being dispersedthroughout the .body of the oil, said reaction product having beenformed by heating said antioxidant material with the oil at atemperature of at least about 250 F., whereby said oil has been renderedhighly resistant to oxidative deterioration.

4. A substantially unoxidized essential oil emulsion normally subject tooxidative deterioration upon standing or heating in the presence of air,said emulsion containing the reaction product of about 2% ofconcentrated fiber and starch free carbohydrate containing water extractof oat flour, said extract being distributed throughout the body of theemulsion, said reaction product having been formed by heating saidantioxidant material with the oil at a temperature of at least about250"F., whereby said emulsion has been rendered highly resistant tooxidative deterioration.

5. The process of stabilizing compositions containing substantiallyunoxidized essential oils, said oils being subject to oxidativedeterioraton and being present in sufflcient quantity in the compositionto produce deterioration of the entire oompositionupon oxidativedeterioration of the oil therein, said process consisting of dispersinga small quantity of an oil insoluble, carbohydrate containing fiber freeand starch free antioxidant material extracted by a solvent selectedfrom the group consisting of water and alcohol from finely divided rawunbleached seeds in said compositions so as to assure thorough mixturewith and contact between the antioxidant material and the compositionand then heating to a temperature in excess of 250 F., whereby saidcomposition-and said oil contained therein are both rendered highlyresistant to oxidative deterioration.

6. The process of stabilizing essential oils which compriseshomogenizing said essential oils in a carbohydrate containing, fiberfree and starch free extract of a cereal, said extract extracted by asolvent selected from the group consisting of water and alcohol from afinely divided, ray, unbleached, low oil and low lecithin containingcereal, said emulsion being subjected to an elevated temperature, atleast about 250 F.

'7. A substantially unoxidized essential oil emulsion normally subjectto oxidative deterioration upon standing in the presence of air, saidemulsion containing the reaction product of a concentrated, fiber andstarch free carbohydrate containing extract of a cereal, said essentialoilbeing distributed as the disperse phase in the body of an emulsioncomprising the extract as the continuous phase, said reaction producthaving been formed by heating said essential oil in the emulsion withthe extract at a temperature of at least about 250 F. whereby saidemulsion has been rendered highly resistant to oxidative deterioration.

SIDNEY MUSHER.

